Quickfuel 3-circuit

Old 06-05-2009, 03:24 PM
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sc4405
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Default Quickfuel 3-circuit

Trying to sort out a Quickfuel 1250 on gas, when running on the stop it's a fat pig and doesn't come off the stop cleanly. Is a 3-circuit carb just wrong for t-stop racing? Currently running a 95 main, .046 idle, .076 intermediate, and unknown HSAB - no digits on it. The O2 shows a big rich spike on the stop and it blubbers it's way through it. Wondering what to do next........ 8) JB
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Old 06-05-2009, 05:05 PM
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I972Nova
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I had one of their 1150's on my car and it was impossible to get a good stop ratio. I went to a Holley hp 2 circuit and its good to go now.

That may be just me though, I dont have good luck with carbs...lol...
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Old 06-06-2009, 09:19 AM
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jmarksdragster
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I built my own 2 circuit 1250 and love it. Start by taking the intermediate bleeds out, put in .025 HSAB's, and jet up to 98 for starters. As long as you don't get an uncurable lean condition at WOT, you can probably plug the intermediate jets as well, it depends on what you have for metering blocks and what mods were made if any. This is a very common issue with a 3 circuit carb. After plugging the 3rd circuit you can't get WOT rich enough I'll get you more info.
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Old 06-06-2009, 10:40 AM
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dparker
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I've heard many complaints on the Quick Fuel carbs. I've heard the 2 circuit is better than the 3 for thottlestop. Check your HSAB with a drill bit, I'd guess its around 35. I don't agree with the 98 jets. Your adjusted air is at 6500ft, 98 jets will be way to much. I would put 93 jets in the main and a 24 to 26 in the HSAB. That will lean out your midrange and still let you have enough fuel on the big end. If you race Hobbs this weekend, I think I have some small air bleeds 24-26.
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Old 06-06-2009, 12:58 PM
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sc4405
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Thanks for the tips Dean-o, I woke up sick'rn a dog this morn, I'm not going anywhere today. Hope it ain't the swine flu......see ya in a couple weeks.. 8) JB
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Old 06-06-2009, 01:01 PM
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jmarksdragster
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Originally Posted by dparker
I don't agree with the 98 jets. Your adjusted air is at 6500ft, 98 jets will be way to much. I would put 93 jets in the main and a 24 to 26 in the HSAB.
93 might be OK for a 1050, but we are talking about a 1250. Mine has 128 BLP jets that are equivalent to around 100 Holley, even the factory Holley 1250 comes with 99's.
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Old 06-06-2009, 03:12 PM
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sc4405
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The quickfuel guys were pretty concerned even with the 94 jet, so I can see your point about the 1250. Probably will start at about 95, since I'll be leaning the int. circuit. Going to call them Monday about changing this to a 2-circuit. 8) JB Edit: It sounds like I should be able to do it no problem.
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Old 06-06-2009, 07:01 PM
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jmarksdragster
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I would suggest at least 1 jet over what the carb came with when removing the intermediates, you don't want to be too lean at WOT. The idea is to get the low and midranges on the lean side, and the fuel curve in the range you run it WOT in as flat as possible. Pulling the intermediate bleeds may make it manageable enough an should show improvement, an as long as the metering blocks have had the mainwells opened enough you should have no issues getting it rich enough and the fuel curve flat without the intermediate circuit.
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Old 06-06-2009, 11:52 PM
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dparker
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Originally Posted by jmarksdragster
Originally Posted by dparker
I don't agree with the 98 jets. Your adjusted air is at 6500ft, 98 jets will be way to much. I would put 93 jets in the main and a 24 to 26 in the HSAB.
93 might be OK for a 1050, but we are talking about a 1250. Mine has 128 BLP jets that are equivalent to around 100 Holley, even the factory Holley 1250 comes with 99's.
Florida has never seen air like we even had today. 6978ft adjusted with 60% humidity. Do you really think 1200ft of air in Florida and your 100 jets is going to take the same jets as 7000ft of air. His O2 sensor is already showing a rich spike in the mid range. I'm sure more fuel going to help his blubbering. I doubt his O2 sensor is showing it way lean on the big end or he would have mentioned it. Even Dan Divinci is usually 10 jet sizes wrong on his advice on jets at this altitude. Maybe you have a magic carb that takes the same jets no matter what the air. Enough for me on jets. My true advice would be to try a APD or Davinci carb. I just don't have to much confidence in Quick Fuel carbs, especially with the quality of parts SC4405 has on his car. It won best appearing car in Dallas(National Event) and has the best of everything other than the CARB.
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Old 06-07-2009, 12:00 AM
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dparker
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To change the subject sc4405, you should have come racing today. J.Wenger and Glen the torke convrter guy(Glen) in the finals tonight with Glen winning his 2nd race in a row today. I think Cotham and Callaway went out in the fifth round. With Wenger going to the finals beating my a## in the fifth round also should give him sole possesion of first in the points.
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